I know it are older posts, but...what do mean exactly with "mods" ?
See, with the open nature, hackers/coders have created steam decky, a sort of...let's say it's comparable to homebrew channel. It extends the options found on the HUD when you click the three-dot button. Installation is a breeze (
here's a quick start guide). But by itself it doesn't do anything. But it allows to easily install, configure, update and delete plug ins that do things like enhancen the brightness, show protondb compatibility and a quick way to change the library pictures.
While this is, strictly speaking, modifying your deck (and thus 'a mod'), it is not a tweak for a specific game. And unless I'm seriously behind on innovations, this really depends and have to be checked per game. Some games are very open ended and allow to install mods by merely installing some files in the game folder(1), others have extended tutorials and executables that had to be run instead of the main executable from the game.
Those latter kinds could be a problem here. The file system is different under linux, so not only might you have to relearn the whole navigation thing, you might need extra hoops to go through to get the mod working. Unfortunately, you can't just run an executable on linux, and there's no "execute using proton" option either. I haven't tested it, but I presume it's the same way as installing custom software:
1) follow the mod's install instructions, replacing the path it says it'll be on windows with where it now is in linux
2) whenever you have to run an executable, you have to first add it to steam, then assign a protondb version to it and then run it.
3) even so, the mod might or might not work.
(1): UT and UT2004 were notoriously easy back in the day: just extract files from a zip archive in the subfolders that the game came with, and you could just pick the new game mode, map, model or whatever straight from the game.
